Control valve and air starting system

ABSTRACT

A method of slow starting a combustion engine with an air starting system having a pressure source coupled to an air starter via a control valve, the method comprising: supplying bursts of air from the pressure source to the air starter by reciprocating a piston of the control valve between an opened position and a closed position.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 14/943,188, filed Nov. 17, 2015, which is incorporated hereinby reference in its entirety.

BACKGROUND

A reciprocating engine, such as an internal combustion engine, is a heatengine that uses one or more reciprocating pistons to convert pressureinto a rotating motion. In a typical example, a piston is housed in asealable piston chamber or pressure chamber, and attached at its base toa rotatable shaft. As the piston slides along the piston chamber, therotatable shaft is rotated, and vice versa.

An air turbine starter (ATS) can be used to initiate the rotation of theengine. The ATS is often mounted near the engine and can be coupled to ahigh pressure fluid source, such as compressed air, which impinges upona turbine wheel in the ATS causing it to rotate at a relatively highrate of speed. The ATS includes an output shaft that is coupled to theturbine wheel and, perhaps via one or more gears, to the engine. Theoutput shaft thus rotates with the turbine wheel. This rotation in turncauses the engine to begin rotating.

The flow of compressed air to the ATS can be controlled by, for example,a valve. This valve is typically referred to as a starter air valve orcontrol valve. When the starter air valve is open, compressed air canflow through the starter air valve, and into the ATS. Conversely, whenthe starter valve is closed, compressed air flow to the ATS can beprevented. A starter air valve, in many instances, includes a pneumaticactuator to move the valve into its open position. The source ofpneumatic power to the actuator can be pressurized air supplied from,for example, an auxiliary power unit (APU), bleed air from anotherengine compressor, etc.

BRIEF DESCRIPTION

In one aspect, the disclosure relates to a method of slow starting acombustion engine with an air starting system having a source ofpressurized air fluidly coupled to an air starter via a control valve,the method comprising: supplying bursts of air from the pressure sourceto the air starter by reciprocating a piston of the control valvebetween an opened position and a closed position, with selectiveapplication of a pull force to the piston to counter, in combinationwith a push force applied to the piston by the pressurized, anormally-closing biasing force acting on the piston.

In another aspect, the disclosure relates to a method of operating anair starting system having a pressure source coupled to an air startervia a control valve, the method comprising supplying bursts of air fromthe pressure source to the air starter to reciprocate a piston of thecontrol valve between an opened position and a closed position, biasingthe piston toward the closed position by applying a biasing force with abiasing element, flowing a fluid from the pressure source to an inlet ofthe control valve to apply a push force on the piston; generating a pullforce on the piston which when combined with the push force issufficient to overcome the biasing force to move the piston to theopened position, and removing at least one of the push force or the pullforce to move the piston to the closed position.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic view of a combustion engine having a crank shaftthat can utilize an air starting system according to an aspect of thedisclosure.

FIG. 2 is a schematic cross-sectional view of a piston in a combustionengine such as the engine of FIG. 1.

FIG. 3 is a schematic view of an air starting assembly rotationallycoupled with the crankshaft of the engine of FIGS. 1 and 2, inaccordance with an aspect of the disclosure.

FIG. 4 is a schematic cross-sectional view of a control valve that canbe utilized with the air starting system of FIG. 3, and is shown in aclosed position.

FIG. 5 is a schematic cross-sectional view of the control valve of FIG.4, and is shown in an opened position.

DETAILED DESCRIPTION

Contemporary starter air valves that can accommodate high flow rates arenot very responsive. High flow rates typically include flow ratesranging from 900 scfm to over 1700 scfm. For example, valves that canaccommodate flow rates of 1700 scfm take more than one second to fullyopen. A response time of one second or more is considered a slowresponse time. Conversely, valves that are very responsive cannotaccommodate high flow. For example, valves that can open in less than100 ms, which is considered a fast response time, can only accommodateflows as high as 300 scfm, flow rates of 300 scfm and below areconsidered low flow rates.

To accommodate high flow rates with existing slow response valves thecommon technique is to start the opening or closing process of the valveahead of when the valve needs to be opened or closed. This can be doneas far as five seconds ahead of time. This requires anticipation orprediction of what the system is going to do, rather than response toreal-time system events and provides a risky approach, especially withtransient systems where conditions are rapidly changing. Aspects of thedisclosure herein provide a control valve assembly and an air startersystem that provide improved valve opening characteristics as comparedto presently known valve assemblies.

Aspects of the disclosure herein can be implemented in any suitableenvironment including, but not limited to, an environment using areciprocating engine regardless of whether the reciprocating engineprovides a driving force or is used for another purpose, such as togenerate electricity. For purposes of this description, such areciprocating engine will be generally referred to as a combustionengine, or similar language. Such a combustion engine can be fueled bygasoline, natural gas, methane, or diesel fuel. Thus, a preliminaryunderstanding of a combustion engine is provided.

FIG. 1 illustrates a schematic view of a reciprocating engine, such as acombustion engine 10, having a rotatable shaft, such as a crankshaft 12,and at least one piston 14 located within an engine block 16. A gearbox19 having a spline gear 21 and one or more internal gears or gear train23 can be included and operably coupled with the crankshaft 12. Asbetter illustrated in FIG. 2, the piston 14 located within thecorresponding portion of the engine block 16 can include a piston head15 rotatably coupled with a piston shaft 17, with the piston head beingslidable within a piston chamber 18 (FIG. 2). The piston shaft 17 isrotatably coupled to a pin on the crankshaft 12, which is radiallyoffset from a rotation axis of the crankshaft, such that rotation of thecrankshaft 12 causes a reciprocation of the piston head 15 within thepiston chamber 18.

While only one piston 14 is shown in FIG. 2, a combustion engine 10typically has multiple pistons 14 contained within corresponding pistonchambers 18, with the pistons 14 being mounted to different pins on thecrankshaft 12, with the pins being radially spaced about the rotationalaxis of the crankshaft 12. The pistons 14 can be arranged in one or morelinear rows, where an engine with only one row of linearly alignedpistons 14 being referred to as an inline arrangement. Engines 10 withmultiple rows of pistons 14 can have an angular spacing between the rowsforming. The pistons 14 can also be radially spaced about the crankshaft12, which is often referred to as a radial arrangement.

The movement of the piston 14 into or out of the piston chamber 18 will,hereafter, be described as “strokes” or “piston strokes.” While thedisclosure can contain descriptions of “upward” strokes, wherein thepiston 14 is moved farther into the piston chamber 18, away from thecrankshaft 12, and “downward” strokes, wherein the piston 14 is removedfrom the piston chamber 18 toward the crankshaft 12, aspects of thedisclosure can include a combustion engine 10 having vertical, or angledstrokes. Thus, the phrases “upward” and “downward” are non-limiting,relative terms for aspects of the disclosure.

As shown, the combustion engine 10 can further include an engine headportion 20 having a sealable air intake passage 22 and a sealableexhaust passage 24. The passages 22, 24 are fluidly coupled with andsealable from the piston chamber 18 via a respective intake valve 26,and exhaust valve 28. Collectively, the piston head 15, engine block 16,head portion 20, intake valve 26, and exhaust valve 28 can define asealable, compression chamber 30.

The head portion 20 can further include a fuel spray nozzle 32 forinjecting a fuel, such as diesel fuel into the compression chamber 30for combustion. While a fuel spray nozzle 32 for injecting diesel fuelis shown, alternative aspects of the disclosure can include the fuelspray nozzle 32 optionally replaced by, in the example of a gasoline ornatural gas engine, a spark plug for igniting an air/fuel or air/gasmixture for the combustion engine 10.

In one example, a combustion cycle the combustion engine 10 can includefour piston strokes: an intake stroke, a compression stroke, acombustion stroke, and an exhaust stroke. The foregoing descriptionassumes the combustion cycle of the engine 10 starts while the piston 14is fully extended upward into the piston chamber 18, which is typicallyreferred to as “top dead center” or TDC. During the intake stroke, arotation of the crankshaft (illustrated by clockwise arrow 34) pulls thepiston 14 out of the compression chamber 30 in a downward intake stroke(in the direction of arrow 38), creating a vacuum in the compressionchamber 30. The vacuum draws in air from the sealable intake passage 22,which is unsealed due to the opening of the intake valve 26 (illustratedin dotted line 40) and timed to correspond with the intake stroke.

Once the piston 14 reaches the lowest point of its intake stroke(illustrated in dotted line 36), the intake valve 26 is sealed, and thepiston begins an upward compression stroke. The compression strokeslides the piston 14 into the pressure chamber 30 compressing the air.At the TDC position of the compression stroke 42, the fuel spray nozzle32 can inject diesel fuel into the compression chamber 30.Alternatively, a combustible fuel can be added to the intake air priorto the intake stroke, or fuel can be added to the compression chamber 30during the compression stroke 42.

Combustion can occur in the compression chamber due to the high heat andhigh pressure of the compressed air/fuel mixture (for example, in adiesel engine), or, alternatively, due to external ignition, such as aspark generated by a spark plug (for example, in a gasoline or naturalgas engine) in the compression chamber 30. During the combustion stroke,the explosion of the air/fuel mixture generates heat in the compressedgases, and the resulting expansion of the explosion and expanding gasesdrives the piston in a downward stroke, away from the compressionchamber 30. The downward stroke mechanically drives the rotation 34 ofthe crankshaft 12.

Following the combustion, the exhaust valve 28 is unsealed to correspondwith the exhaust stroke, and the piston is driven upward into thecompression chamber 30 to push the combusted, or exhaust gases, out ofthe compression chamber 30. Once the piston 14 returns to the TDCposition in the piston chamber 18, the combustion cycle of the engine 10can then be repeated.

While a typical combustion engine 10 can have a set of pistons 14 andpiston chambers 18, a single piston 14 is illustrated and described herefor brevity. It will be understood that “a set” as used herein caninclude any number including only one. In a combustion engine 10 withmultiple pistons 14, the pistons 14 can be configured along thecrankshaft 12 to stagger the piston 14 strokes, such that one or morepistons 14 can be continuously providing a driving force to rotate thecrankshaft 12, and thus drive the pistons 14 through additionalcombustion cycle strokes. The mechanical force generated by the rotationof the crankshaft 12 can be further delivered to drive anothercomponent, such as a generator, wheels, or a propeller.

FIG. 3 illustrates an exemplary schematic configuration of an airstarting system 44 such as for the combustion engine 10. The airstarting system 44 can include an air starter 52 fluidly coupled with apressure source 54 via a control valve 56, and a controller 58 orprocessor.

The air starter 52 is shown further including a body portion 70, astarter output 72, illustrated as a gear, having a set of teeth 74 keyedto mesh with the spline gear 21 of the gearbox 19, which is operablycoupled to the crankshaft 12. It will be noted that this is typicallythe arrangement for starters on gas turbine engines. For starters onreciprocating engines, an external spur gear on the starter drive shaftcan drive a large external spur gear or ring gear on the engine and suchan engine ring gear can be coupled to the engine drive shaft.

A starter sensor 64 can also be included and be configured to sense ormeasure characteristics of the air starter 52, for example, therotational speed of the starter output 72, the torque generated by thestarter 52, etc. The sensor 64 can be further capable of generating ananalogue or digital signal representative of the startercharacteristics, and can provide the generated signal to the controller58. Aspects of the disclosure are envisioned wherein the starter 52 is,for example, mechanically or removably mounted to the engine 10.Alternatively, the starter 52 can be capable of controllably extendingand retracting the starter output 72 portion of the starter 52, suchthat the teeth 74 can be engaged or disengaged only during startingoperations. Additional configurations are envisioned.

The controller 58 can further include memory 78 including, but notlimited to, random access memory (RAM), read-only memory (ROM), flashmemory, or one or more different types of portable electronic memory,such as discs, DVDs, CD-ROMs, etc., or any suitable combination of thesetypes of memory. The controller 58 can be operably coupled with thememory 78 such that one of the controller 58 and the memory 78 caninclude all or a portion of a computer program having an executableinstruction set for controlling the operation of the control valve 56and air starter 52. The program can include a computer program productthat can include machine-readable media for carrying or havingmachine-executable instructions or data structures stored thereon. Suchmachine-readable media can be any available media, which can be accessedby a general purpose or special purpose computer or other machine with aprocessor. Generally, such a computer program can include routines,programs, objects, components, data structures, algorithms, etc. thathave the technical effect of performing particular tasks or implementparticular abstract data types. Machine-executable instructions,associated data structures, and programs represent examples of programcode for executing the exchange of information as disclosed herein.Machine-executable instructions can include, for example, instructionsand data, which cause a general purpose computer, special purposecomputer, controller 58, or special purpose processing machine toperform a certain function or group of functions.

The control valve 56 has been illustrated as including a housing 80defining a flow passage 82 with an inlet port 84 fluidly coupled to thepressurized air source 54 and an outlet port 86 fluidly coupled to theair starter 52. The flow passage can be sized in any suitable manner forthe system including, but not limited to, that the flow passage 82 canbe sized to permit a flow rate of at least 900 scfm. It is contemplatedthat the flow passage 82 can be sized to accommodate flow rates at leastup to 1700 scfm. A valve body 88 movable between an opened position 90and a closed position 92 (shown in phantom) to selectively open andclose the inlet port 84 resulting in a corresponding opening and closingof the control valve 56 is also included. While the valve body 88 isillustrated as selectively opening and closing the inlet port 84 it willbe understood that the valve body 88 could alternatively selectivelyopen and close the outlet port 86 or another portion of the flow passage82.

A linear motor 94 can be operably coupled to the valve body 88 to movethe valve body 88 between the opened and closed positions. The linearmotor 94 can move the valve body 88 in response to a control signalsupplied by the controller 58. Further, the linear motor 94 can beconfigured to move the valve body 88 between the closed and openedpositions in a response time of 30 ms or less. By way of furthernon-limiting example, it is contemplated that the linear motor 94 canmove the valve body 88 between the positions in 25 ms or less. Thelinear motor 94 has a large travel distance as compared to a typicalsolenoid motor and this allows the linear motor 94 to move the valvebody 88 fully between the opened and closed positions. Further, duringoperation the pull force generated by the linear moto 94 combined withthe push force of the pressurized air move the valve body 88 away fromthe inlet port 84 within the desired response time.

During operation, the air starter 52 and control valve 56 operate togenerate force, such as a torque at the starter output 72, in responseto a provided supply of air pressure. The torque generated by the airstarter 52 is applied (via the spline gear 21, gear train 23, andcrankshaft 12) to generate the compression force used by the compressionstroke 42 to compress the contents of the compression chamber 30. By wayof non-limiting example, the air starting system 44 can be utilized forslow starting the combustion engine 10, wherein the slow starting of thecombustion engine 10 prevents damage to the engine 10 if the compressionchamber 30 contains an incompressible fluid, such as water. As usedherein, “slow starting” is used to describe rotating the crankshaft 12at a speed below operational or self-sufficient running, engine speed,such as an idle speed. The slow speed, or “slow roll” operation of themethod can allow for issues or concerns regarding proper engineoperation to be identified before any internal damage can occur to theengine 10. The air supplied by the control valve 56 to the air starter52 can be non-continuous due to the low speed operation necessary foradequate slow roll performance. For example, the controller 58 cancontrol the control valve 56 to provide bursts of supply air to keep thecrankshaft moving at predicted or target speed.

FIG. 4 illustrates an exemplary control valve 156 according to an aspectof the disclosure and that can be utilized in the air starting system 44as described above. The embodiment of the control valve 156 is similarto the embodiment of the control valve 56. Therefore, like parts will beidentified with like numerals increased by 100, with it being understoodthat the description of the like parts of the control valve 56 appliesto the control valve 156, unless otherwise noted.

As with the previous embodiment, the control valve 156 has a housing 180with an inlet port 184 and an outlet port 186 formed in the housing 180.A flow passage 182 (FIG. 5) is defined through an interior 198 of thehousing from the inlet port 184 to the outlet port 186.

One difference is that the valve body 188 is illustrated as including apoppet or piston 200 having a head 202 and a shaft 204 extending fromthe head 202. The piston 200 is reciprocally movable between opened andclosed positions for opening and closing the inlet port 184.Alternatively, the valve body 188 can be designed such that the piston200 is reciprocally moveable between opened and closed positions foropening and closing the outlet port 186.

The piston 200 can be designed in any suitable manner including, but notlimited to, that the head 202 can include a lower end 206 defining anopening 208 to a recess 210. Further, a seal in the form of an O-ring211 has been illustrated as being operably coupled to the head 202. Whenthe head 202 is in the closed position the O-ring 211 abuts the housing180 and aids in sealing the inlet port 184.

Another difference is that the linear motor 194 is illustrated asincluding a housing 212. The housing 212 of the linear motor 194 can beshaped in any suitable manner and can be fixed to the housing 180 of thecontrol valve 156. Further, as illustrated, the linear motor 194 caninclude a permanent magnet 214 mounted to the shaft 204 of the piston200 and an electromagnetic coil 216. The permanent magnet 214 resideswithin the housing 212 of the linear motor 194 and at least a portion ofthe shaft 204 extends into the housing 212 of the linear motor 194.

As illustrated, the electromagnetic coil 216 can be included within thehousing 212 and circumscribes the shaft 204. At least a portion of thehousing 212 of the linear motor 194 can be provided within the recess210 of the head 202. In this manner, at least a portion of theelectromagnetic coil 216 can lie within the head 202. Theelectromagnetic coil 216 defines an interior 218 and the shaft 204extends through the interior 218 such that the permanent magnet 214 canreciprocate through the interior 218. In this manner, the linear motor194 and its components can be integrated into or located within thevalve body 188 and this provides a compact control valve 156.

Further, a biasing element 220 is included in the control valve 156 andapplies a biasing force to the piston 200 to urge the piston 200 to theclosed position (FIG. 4). Any suitable biasing element 220 can beutilized including, but not limited to, a compression spring or a coilspring 222 as illustrated. The coil spring 222 has one end 224 abuttingthe head 202 of the piston 200. In the illustrated example, the coilspring 222 circumscribes the housing 212 of the linear motor 194 and atleast a portion of the electromagnetic coil 216 although this need notbe the case.

Bearings can be included within the control valve 156 to facilitatemovement of the shaft 204. For example, a first bearing 230 isillustrated as being mounted to the housing 212 of the linear motor 194and circumscribing the shaft 204. A second bearing 232 can be mounted tothe housing 180 and circumscribe the shaft 204. More specifically, thebearing 232 is illustrated as being mounted within a flange 233. It willbe understood that any number of additional suitable seals or flangescan be included within the valve 156. Both the first and second bearings230 and 232 allow for linear movement of the shaft 204 when the head 202is moved between the opened and closed positions. Further still, avariety of seals 234 can be utilized to seal portions of the controlvalve 156 from the pressurized air.

When electricity is passed through the electromagnetic coil 216 itgenerates a magnetic field that interacts with the magnetic field ofpermanent magnet 214 to apply a force to the shaft 204 sufficient toovercome the biasing force of the biasing element 220. Morespecifically, when electricity is passed through the electromagneticcoil 216 it generates a magnetic field that moves the permanent magnet214, causing a corresponding movement of the piston 200, resulting inthe head 202 moving from the closed position (FIG. 4) to the openedposition as illustrated in FIG. 5. This allows pressurized air to flowfrom the inlet port 184 through the flow passage 182 to the outlet port186. The linear motor 194 moves the head 202 between the closed andopened positions in a response time of 30 ms or less.

During operation of the pressure source 54, pressurized air is receivedat the inlet port 184. The force of the air acts on the valve body 188to try and push the valve body 188 away from the inlet port 184 and openthe control valve 156. The coil spring 222 and the linear motor 194produce a force that counteracts the pneumatic force of the pressurizedair and keeps the control valve 156 closed. More specifically, absent acountering force from the linear motor 194 the coil spring 222 urges thevalve body 188 closed. Further, when voltage with a specific polarity isapplied to the electromagnetic coil 216, the magnetic field produced bythe electromagnetic coil 216 interacts with the magnetic field of thepermanent magnet 214 and produces a force that drives the piston 200towards the inlet port 184. The O-ring 211 in the valve body 188 sealsagainst the valve housing 180, and the valve body 188 closes andprevents air from entering the inlet port 184.

When the control valve 156 is to be opened, the voltage polarity on thelinear motor 194 is reversed. With current flowing the oppositedirection through the electromagnetic coil 216, a force is generatedthat acts to pull the valve body 188 away from the inlet port 184. Thepull force generated by the linear motor 194, combined with the pushforce of the pressurized air, moves the valve body 188 away from theinlet port 184, allowing air to enter the inlet port 184 and exitthrough the outlet port 186.

Conversely, when the control valve 156 needs to close again, the voltagepolarity on the linear motor 194 is reversed once again, and the forceof the linear motor 194 and force of the coil spring 222 act to push thevalve body 188 back towards the inlet port 184, sealing the inlet port184 to the pressurized air, closing the control valve 156 once again. Bycycling the voltage polarity of the linear motor 194, the control valve156 can be quickly opened and closed to rapidly modulate the flow of airthrough the control valve 156.

The above-described embodiments provide a variety of benefits includingthat a fast response pneumatic valve can fully open in approximately 30ms, can modulate inlet pressures as high as 50 psig, can open with inletpressures as high as 150 psig, and can accommodate flow rates at leastas high as 1700 scfm. The above-described embodiments can beelectrically actuated and can be utilized in systems that requireintroducing high air flow in a relatively short period of time. Further,the above-described embodiments can be utilized in systems that requirecutting off high air flow in a relatively short period of time. Further,the size and weight of the above-described embodiments are smaller,lighter, more reliable, and less costly than contemporary solutions andthe above-described embodiments do not rely on internal feedback andprovide basic on/off functionality.

Further still, the above-described embodiments provide real timeresponse and live feedback and therefore can be utilized in systems thatrely on closed-loop feedback. More specifically, when a signal is givento the above-described embodiments, the output response, in terms of airflow scfm, is targeted to occur within 30 ms or less. Such a minimal lagbetween an input signal and output response is critical for pneumaticsystems that utilize relatively high flow rates and need real-timeresponse to live feedback. For example, the minimal lag is importantduring a slow roll start because the starter system will otherwise notshut off in time and if there is a problem, such as when there is waterin the cylinder heads, the engine can be damaged as the pistons continueto reciprocate.

To the extent not already described, the different features andstructures of the various embodiments can be used in combination witheach other as desired. That one feature may not be illustrated in all ofthe embodiments is not meant to be construed that it cannot be, but isdone for brevity of description. Thus, the various features of thedifferent embodiments can be mixed and matched as desired to form newembodiments, whether or not the new embodiments are expressly described.All combinations or permutations of features described herein arecovered by this disclosure.

This written description uses examples to disclose the aspects of thedisclosure, including the best mode, and also to enable any personskilled in the art to practice the aspects of the disclosure, includingmaking and using any devices or systems and performing any incorporatedmethods. The patentable scope of aspects of the disclosure is defined bythe claims, and can include other examples that occur to those skilledin the art. Such other examples are intended to be within the scope ofthe claims if they have structural elements that do not differ from theliteral language of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal languages ofthe claims.

What is claimed is:
 1. A method of slow starting a combustion enginewith an air starting system having a source of pressurized air fluidlycoupled to an air starter via a control valve, the method comprising:supplying bursts of air from the pressure source to the air starter byreciprocating a piston of the control valve between an opened positionand a closed position, with selective application of a pull force to thepiston to counter, in combination with a push force applied to thepiston by the pressurized air, a normally-closing biasing force actingon the piston.
 2. The method of claim 1 further comprising flowing afluid from the pressure source to an inlet of the control valve toproduce the push force on the piston.
 3. The method of claim 1 furthercomprising closing the valve by applying a biasing force on the pistonwith a biasing element.
 4. The method of claim 3 wherein moving thepiston to the opened position occurs when the push force and the pullforce in combination overcome the biasing force.
 5. The method of claim1 further comprising linearly moving a shaft connected to the piston tomove the piston between the closed and opened positions with a linearmotor coupled to the shaft.
 6. The method of claim 5 further comprisingpassing electricity through an electromagnetic coil to generate amagnetic field that interacts with a permanent magnet to apply a forceon the shaft.
 7. The method of claim 6 wherein passing electricitythrough the electromagnetic coil in a first direction generates the pullforce on the shaft.
 8. The method of claim 7 wherein passing electricitythrough the electromagnetic coil in a second direction opposite thefirst direction generates a pushing force on the shaft pushing thepiston toward the closed position.
 9. The method of claim 1 furthercomprising forming a flow passage between an inlet of the control valvefluidly coupled to the pressure source and an outlet of the controlvalve fluidly coupled to the air starter when the piston is in theopened position.
 10. The method of claim 9 further comprising flowingpressurized air from the inlet to the outlet.
 11. The method of claim 10wherein the pressurized air is flowing at a flow rate is up to andincluding 1700 scfm.
 12. The method of claim 1 wherein moving the pistonfrom the closed to the opened position occurs in 30 ms or less.
 13. Themethod of claim 1 wherein the piston moves from the closed to the openedposition when an inlet pressure is up to and including 150 psig.
 14. Amethod of operating an air starting system having a pressure sourcecoupled to an air starter via a control valve, the method comprising:supplying bursts of air from the pressure source to the air starter toreciprocate a piston of the control valve between an opened position anda closed position; biasing the piston toward the closed position byapplying a biasing force with a biasing element; flowing a fluid fromthe pressure source to an inlet of the control valve to apply a pushforce on the piston; generating a pull force on the piston which whencombined with the push force is sufficient to overcome the biasing forceto move the piston to the opened position; and removing at least one ofthe push force or the pull force to move the piston to the closedposition.
 15. The method of claim 14 further comprising linearly movinga shaft connected to the piston to move the piston between the closedand opened positions with a linear motor coupled to the shaft.
 16. Themethod of claim 15 further comprising passing electricity through anelectromagnetic coil to generate a magnetic field that interacts with apermanent magnet to apply a force on the shaft.
 17. The method of claim16 wherein passing electricity through the electromagnetic coil in afirst direction generates the pull force on the shaft.
 18. The method ofclaim 17 wherein passing electricity through the electromagnetic coil ina second direction opposite the first direction generates a pushingforce on the shaft pushing the piston toward the closed position. 19.The method of claim 14 further comprising forming a flow passage betweenthe inlet and an outlet of the control valve fluidly coupled to the airstarter when the piston is in the opened position.
 20. The method ofclaim 19 further comprising flowing pressurized air from the inlet tothe outlet.